Law of Reciprocals
by thequeergiraffe
Summary: John has always been a good friend. Sherlock is just trying to reciprocate. Shameless fluff ensues. Rated for depictions of violence.


**i. Reciprocation**

Three days ago I came closer to dying (_actually_ dying) than I have in years. To say it was something of a surprise to me, I think, would be a slight understatement. Unfortunately there was no way, outside of precognition (which I don't believe exists, having assessed the evidence), that I could have known that an accidental bludgeoning was in store for me as I chased a serial murderer and his cohort through the docks. By sheer coincidence the two men I was following managed to run past before the fisherman began unloading their take; I, however, was not so lucky. It sounds amusing, being hit over the head with a large frozen fish, but I can assure you it really, really isn't. Especially when one's head injury causes one to fall into the Thames, which can look rather mild but which tends to have a severe and overpowering undercurrent. Thus I wound up unconscious and being dragged under filthy water, the assailants still fleeing the scene and the fishermen (I've heard) gawking at me from the safety of the docks.

Thankfully, John was just behind me. Naturally I didn't bear witness to this part of the story, but I'm told that John leapt into the water immediately and without the slightest hint of hesitation, despite shouts from Lestrade attempting to dissuade him. John managed to pull me up to the surface (I will forever lament the loss of my coat, which I presume has wended its way out to the Atlantic Ocean by now- or down into the muddy mess at the bottom of the river- and which John correctly proclaimed as too heavy and thus discarded while still in the water) and keep me from drowning entirely until we could both be rescued by a police boat. The rest of the story is typical: I was taken to the hospital, where I woke up spluttering and cold, and made to stay overnight despite having a live-in doctor. John was there all the while, and though we both reeked horribly (the Thames isn't known for its pleasant smell) he seemed inordinately pleased to sit beside me all night, neither of us sleeping.

If you're curious, the murderer escaped, but the cohort was caught and I expect he will tell us what we need to know as soon as he realizes how uncomfortable prison life can be. But that's not the part of the story I've been musing on for these last two days. Instead, I've been considering John Watson.

"John?" I call. I can hear him bumbling around in the kitchen right now, making tea as I sit in my chair and fiddle with my violin's bow.

"Yeah?"

"You saved my life."

Momentary silence. "Yeah?"

"You've done so several times now."

I can hear him chuckling. "Law of Reciprocals, is it? You've saved mine enough times. I figure, turnabout's fair play."

What? "No, no. Are you thinking of Newton's third law of motion?" And he takes the piss out of me for not caring about the solar system. "Elementary physics, John. If that's what you're thinking of, then your reaction should have been equal and _opposite_. You should have let me drown."

John appears from the kitchen: two mugs; dishwater hair; burgundy cardigan; plaid button-up and cords; slight signs of fatigue present in his under-eyes and the line of his shoulders; pleasant facial expression; socks but no shoes. "All right," he says, the shadow of a smile making itself known in his eyes and at the corners of his lips, "so I'm no physicist." He presses a warm mug into my hands and says, "My point was: reciprocation is basically the foundation of friendship, right? Not that I would have hesitated if you'd never saved my life before, God no, but knowing that you'd do the same thing for me makes those kinds of choices easy. It's…simple loyalty. Never expected to find _that _in civilian life." He chuckles and then, bizarrely, leans down and kisses my forehead where my brow is furrowed with thought.

My eyebrows shoot up but he doesn't notice, already shuffling towards the sofa and yawning tremendously. Why does this man, who was just filthy with river water and reeking of sewage and rot only three days ago, seem so content? It's…almost hateful, but not quite because it's John and I don't find John's contentment boring or bothersome. Instead, I'm vaguely intrigued.

Reciprocation.

Hmm.

**ii. The Initial Gesture**

We're at a crime scene. It's been over a week since the near-drowning and my mind is whirling. Mainly because this corpse is being at least somewhat interesting. A John Doe; I like those. His shoes are shined and mostly free of dirt or city grime, but the backs of the hems of his trousers are muddy. Airport, then, and in the last twelve hours or so. (No one gets their shoes shined anywhere else, not anymore.) ID missing but then so is the entire wallet, so that's no surprise. Simple robbery? But then why not take the jewelry? That watch is expensive; if the killer was a mere thief, he (statistically speaking, he) should have taken it. The ring, as well. But the mobile's gone; business man, undoubtedly he has a mobile and undoubtedly it would have been kept in the left trouser pocket, because the man is left-handed. And yet, it's missing. Hmm.

But: I'm also thinking about John. If he truly believes that reciprocity is the foundation of friendship, he must consider me an appalling friend. I don't reciprocate his kindnesses. I've never seen reason to, not until now. But I enjoy John's company (clearly, I learned that while abroad, certainly, among other things) and I don't wish to upset him. So…?

I stand and walk over to where John is kneeled, examining the corpse's head (hairplugs: vain, decent salary, probably had a mistress) with keen interest. "John."

He looks up at me with startlingly blue eyes (why startling? haven't they always been blue? and yet…) and gives me his best _at-your-command _expression, carefully patient and mildly eager. "Got something?"

"I…" I'm faltering. "I'd like to reciprocate."

John's left eyebrow lifts minutely. "Okay."

Grasping him by the elbows, I heave him up to his feet and lean over, planting a small, gentle kiss on his forehead. His skin is softer than I expected, here at least. I can smell him better this close too, that familiar scent that is something like tea and damp wool and warmth. Indescribable, really, but only just. When I pull away, my lips feel strange; "buzzing" isn't quite the right term, but it's the closest I can muster.

John's face is pink and his eyes are wide; a few of the Yarders are snickering and cat-calling. Oh. "Not good?"

Swallowing, John opens his mouth, closes it again. "That's…it's fine, that was fine," he says at length, looking at once bewildered and amused. I'm not hurt by his amusement; it's the fond kind, the kind John often displays when I've done something odd but undamaging.

I release his elbows (have I really been holding them this whole time?) and take a step back. "It wasn't a romantic gesture," I clarify, because the Yarders are still snickering behind us.

"Okay," John says quickly. "Good. And, uh, when I-" He leans in a bit, drops his voice. "When I did it? That wasn't a romantic gesture, either. It was just…protective."

Protective. I approve of that. John and I protect each other. I nod and turn my attention back to the body. "The wife, I suspect. She knew he'd be mixing business with pleasure on his trip to London, didn't approve." My deductions tumble on, but I still notice when John's eyes go unfocused and his fingers brush the crease of his brow thoughtlessly.

**iii. Extraordinary**

John compliments me often. Generally the compliments are well-deserved; I am, after all, incredible. But if reciprocation is something he's after, I'm doing a rather pitiful job.

So today, four days after the kiss at the crime scene, I've decided to give this another go. I think the last gesture was something of a failure, unfortunately, because John's been giving me strange looks and blushing in front of Lestrade (discomfort certainly wasn't my goal, that should be obvious) so I'm going to try this instead. If John does something really well today, I intend to compliment him thoroughly for it.

Here's my chance: John's brought me tea. I'm at the kitchen table, using his laptop to do some research on fainting goats and whether or not that phenomenon appears in humans at all. It's very easy to smile warmly at him as he sets my mug down, easier than I expect it to be, and as I take a careful sip (gauging the temperature somewhat unnecessarily as John always waits until it's cooled to bring it to me) I notice it's perfectly done to my taste. Excellent.

"Mmm," I say, making a noise that should translate to satisfaction. "Amazing."

John looks at me dubiously. "I didn't do anything special," he says, looking at his own mug worriedly.

"No, no," I insist, taking another sip and giving him an appreciative look. "This tea is extraordinary. Stupendous. Best tea I've ever had, in fact." That last bit is a lie, but John doesn't seem to be taking to this as well as I'd expected.

He's still staring at his own tea. "Sherlock? Have you done something to the mugs? Or…or the sugar?" He meets my eyes. "I've told you more times than I can count, if you're going to experiment on me or Mrs. Hudson-"

I set my mug down roughly. Why isn't this working? "I'm not experimenting on anyone! I was simply remarking upon your well-cultivated ability to make a superb cup of tea. That's all."

John's eyes widen, and then his face softens. "Oh," he says, drawing the syllable out. "Okay. Thank you, Sherlock."

"You're…you're welcome," I say, thrown by his sudden acceptance. Has he got the right idea, or the wrong one? Should I clarify that _this _isn't a romantic gesture, either, or will that make things awkward? This is exactly why I never bother with social niceties. I wind up floundering and making a fool of myself. And I don't suppose I can just ask him to delete this; ordinary people don't work that way. Standing suddenly, I announce, "I'll be in my room," at which point I realize I _never _announce where I'm going and bound down the stairs to Mrs. Hudson's flat instead, where I pester her for nearly two hours about the state of her manicure and its implications upon her relationship with the florist down the street.

**iv. Some Things Only Make Sense When One Party Is Drugged**

The following night I tip-toe up the stairs to John's room and listen at the door. I don't hear anything that would suggest impropriety, so I open the door without knocking and step inside.

John looks up at me from over his reading glasses. "All right?" he asks, turning his book over and laying it astride his lap. (Reading "for fun", I'll never understand it.)

"I seem to recall you tucking me in once," I explain, crossing the room and standing a bit awkwardly by the bed. I gesture to the book. "I can wait-"

John laughs- not the little chuckle he normally doles out, but a full, deep-throated laugh- and shakes his head. "You don't have to," he says, but he shuts his book and sets it on the nightstand anyway, placing his glasses gently on top of the book. "Seriously. It's fine either way. I'm not opposed but…don't feel obligated to echo every nice thing I've ever done for you, Sherlock. I mean it."

"I don't feel obligated," I reply, surprised to find I mean it. "This is something I would like to do."

Shaking his head again, John slides down into his bed and settles his head on the pillow, looking up at me. I'm not sure what to do now but I'm reasonably certain it involves blankets…ah, yes, there we are. I tug John's blanket up to his chin. "Right," I say. What did he do when he was tucking me in? Oh, that's right. I pat his chest and add, "If you need anything, I'll be downstairs."

John giggles and runs his hand down his face, mussing his blankets. "Good night, Sherlock," he says, voice thick with amusement.

"Good night, John." I click off his lamp and make my way quietly to the door.

When I reach the threshold, John says, "Sherlock?" and I pause, turning back. "You can stay, if you want," he says softly. My pulse elevates; why?

"Why would I stay?" I ask, my voice as quiet as his.

"You- you don't have to. Only I know you…" He pauses, sits up a little. "Only I know you watch me sleep sometimes," he admits, like it's a secret. "If you wanted to tonight, I don't mind."

I've spent all of my spare time this week collecting pigeon feathers from various points across the city. Tonight I was planning to study them and collect data regarding what, if any, differences they might reveal. I've been greatly looking forward to this…but I'm still taken by the odd compulsion to sit beside John and watch him fall asleep. I've never done that, not in here. On the sofa, in cabs sometimes, waiting at the hospital. But I've never seen him fall asleep in his own bed. I'm suddenly, desperately curious as to what _exactly_ that looks like.

"It's all right, Sherlock," John says, and I realize I've let the silence stretch on too long. "You don't have to. Good night." He lies back down fully, pulling the blankets back up around him, and would it be strange now if I said I wanted to? It would be; I'm sure.

"Good night, John," I whisper, and I pull the door closed behind me silently as I leave.

**v. Battle of the Blogs**

Another failure, but I think I was much closer last time and so I'm willing to try again. I've considered some of the other ways John displays our friendship and I've come across the perfect solution. John regularly features stories about me on his blog. Usually they're case studies, but sometimes he writes about the mundane details of day-to-day life at 221B, claiming his audience clamors for it.

I can do that.

I follow John around all morning, making notations in a small moleskin notebook. He tries half-heartedly to shoo me away, initially, but by breakfast he gives it up for a lost cause and ignores me completely. Perfect.

When he leaves the flat to pick up some shopping and lunch around noon, I pull out his laptop and settle on the couch, flipping through my data and deciding how best to compile it. John likes narratives, so I settle on that. Opening up a new post, I begin to type:

_This morning John woke up at 06:34:12. Although my observations were conducted in the hallway outside his room, I was able to deduce that he spent several moments stretching, yawning, and apparently scratching himself. He then muttered "all right, you" and got out of bed at 6:35:26. Then he performed fifty push-ups and forty-eight sit-ups, though he intentionally miscounted the latter as fifty as well. At this point John generally takes a shower, so I went downstairs and waited for him to go into the bathroom before continuing my observations. John's usual showers last approximately nine minutes. This morning's shower lasted for ten minutes, thirty-seven seconds. It seemed possible that the extra time was masturbatory in nature; however, upon his leaving the bathroom it became clear to me that this was not the case. (Pupils normal; skin only slightly flushed from warm water; posture too tense; pulse observably regular.) I examined the bathroom and found the cause to be two-fold: John was clipping his toe-nails and, judging by the amount and length of the hairs in the sink, his nose hairs. _

I continue in this vein at great length, recording for posterity every detail of John's morning and hitting "post" with an exuberant smile. He should be pleased, I suspect.

Except, when he comes home pink-faced and agitated, I discover he isn't.

"Why?" he whinges, slapping bags of food down on the kitchen table. "Why am I getting phone calls from Lestrade saying you've posted about my nose hair and masturbatory practices on your blog?"

"I thought you would be flattered," I say, echoing his own sentiment from years before without entirely meaning to do so.

John recognizes the phrase. He pauses, eyes meeting mine. "Are you angry with me?"

"Not at all." Damn. "I was being reciprocal."

"Look, if it's because I asked you to stay-" John says, looking uncomfortable and guilty.

"No!" _Damn. _I've messed this one up entirely. "I almost did stay, except there were pigeon feathers and…John, I _honestly _thought you'd be flattered."

John's shoulders relax. "Really? Because if you were weirded out-"

"I wasn't," I maintain. "I'd like to watch you tonight, in fact. If I may." Oh. Those words tumble out of my mouth completely unbidden.

But John's slow smile is an excellent reward. "Okay. All right." He slaps his hands together and rubs his palms, letting out a breath. "Tea?"

**vi. Who Says Chivalry Is Dead?**

Boathouse. Stains on the little rug in front of the sink (cheap; new; tacky) and the curtains (old; second-hand) from blood splatter, wiped nearly clean by a dishrag soaked in bleach and water. Bleach smell in the sink. Bleach smell on the gloves under the sink. Bleach smell here on the floor, where I'm lying with my arms spread and my neck lolled.

Yes. She must have lain just like this.

I turn my head (what would she have seen in her last moments? something useful?) and get an eyeful of John's jean-clad crotch. Hmph. I look up and clear my throat. "John," I say, rather patiently by my estimation, "I doubt very seriously that you were squatting beside the victim as she died, and thus I doubt very seriously that her dying view was your…" I wave my hand dismissively towards his anatomy, and he flushes and stands, moving out of the way.

"Sorry," he winces, still red all over. I don't pay him any mind. The door; I can see under the door from here. If someone else were coming I would know, and I might try to scoot back-

The titters of the new forensics intern and Anderson (_Anderson_, still) distract me. "It's pathetic, isn't it?" Anderson stage whispers. "Bad enough to be so disgustingly in love with a complete and utter freak, but to be _rejected_ by him and still follow him around like a hopeless puppy-"

I'm on my feet almost instantaneously. Anderson's nose crunches against my fist with a satisfyingly squicky noise and I relish this, the sight of his clutching his face and oozing blood, before snapping, "Go, get out, before you bleed all over my crime scene." I think it's the man's shock that causes him to listen so quickly and without argument. The intern, perhaps fearing for her own nose (and after that expensive surgery for her "deviated septum" I suppose those fears are well-founded), disappears after him. I glance over at John, who is looking at me with something very much like awe.

"I…" he says, then stops, blinking.

"Anderson wet the bed until he was fifteen," I blurt. "His IQ is probably in the double-digits. Ignore him; he's an imbecile."

"Thank you," John says, still looking at me with that strange, awed expression.

And there, I've done it. I've "reciprocated". John once punched a police officer in the face for defaming me; now I've done the same. Flawlessly, I might add. Finally.

John is standing almost exactly in the place where a woman died mere hours before, the scent of bleach still sharp in the air (and underneath it, the copper tang of a great quantity of blood). There's a meager shaft of light breaking through the curtains, dust motes dancing in the air in front of John, but the overhead lighting is paltry and yellow-ish, casting the room in a sickly dimness. Even so, I can't look away from John. I was right before: his eyes are _startlingly _blue.

"Sherlock, I…" he says, trailing off again. He swallows; reflex; he's going to say something that frightens him. "He's right. I love you."

My eyes widen. Ah. Now we've reached the crux of the thing. "Love is for women and idiots," I say, uncomfortably aware of the way his face immediately closes off. "Not that the two categories are mutually exclusive." I take a step forward and stop again. "But I would die for you. Have done, in fact. Is that good enough?"

John licks his lips and his eyes lighten. "Yeah," he says, after a moment. "Yeah, I think so."

"Good," I say, my heart slowing down a little now. I clear my throat. "Now tell me, if you were bleeding to death and you saw someone's feet there-" I point to the crack under the door. "-what would you do?"

**vii. Round and Round The Garden (Like A Teddy Bear)**

"I know he can be difficult," Lestrade says, shifting in his chair. He doesn't like Anderson; he approves of what I did; he's only reprimanding me because of the demands of a higher authority. "But I can't have you assaulting my team, Sherlock. No matter how obnoxious you find their faces to be."

"Astoundingly," I drawl, "Anderson's face wasn't the most off-putting thing about him yesterday. He said something very rude about John, and I won't stand for it."

Lestrade's eyebrows raise and his gaze flickers to John, who is sitting in his _I-was-a-soldier-y'know _pose, legs set wide, arms crossed, face glowering. "You can file an official complaint, if you'd like," Lestrade suggests.

"No, thank you," John says, polite despite his irritation.

I'm not polite, ever, and I won't start now. "I think he rather got the idea," I smile, "and if not, I'll be happy to reintroduce it to him as many times as I deem necessary." I stand abruptly. "Are we done here?"

"Now hang on-" Lestrade blusters, making a show of standing as well.

John interrupts him, his voice steady and calm. "If Anderson decides to lodge a formal complaint against Sherlock, we can deal with this then. Until then, Greg, really, why are we pretending that seeing Anderson snivel over a bloody nose isn't something we've all wanted for years?"

"Fair point," Lestrade sighs resignedly, sinking into his chair with a small smile. "But if anyone asks, I shouted abuse at the two of you for _hours_."

"Deal," John grins.

I grab John's arm and begin pulling him out of the office after me. "Make sure the next one is more interesting, Lestrade!" I call, releasing John when I'm sure he's following me.

"You bloody madman," John says, still grinning, as we stand together in the lift. He bumps me with his elbow. "Listen, I know what you've been doing lately and I…well, I-I got you something." I look at him curiously, but my jaw drops as he pulls Lestrade's ashtray from his coat. Lestrade isn't meant to have an ashtray in his office, a) because he "quit" and b) because it's illegal to smoke indoors, but I've always known about the ashtray he kept in the bottom drawer of his desk "just in case" along with a lighter and a pack of cheap cigarettes. I didn't think John knew, though, and that combined with the obvious mirroring of the time I stole an ashtray for him (the one that sits on our mantle even today, the one from Buckingham Palace)…

There's no denying this is a romantic gesture.

I'm not sure what to say. (I know what I do say, which is only "_John_".) I don't even know what to think or do. I know there's an odd sensation in my chest, a sort of swelling that makes me feel light-headed and a little off-kilter. I hear myself speak, only to say again: "John."

The lift stops; the doors open; we don't move. They slide closed again. I don't break eye contact with John as I reach over and hit the emergency stop button between floors. "I like watching you sleep," I say, because it feels important.

John smiles. "I know."

"Your daily routine fascinates me despite it having remained essentially unchanged in all the time we've lived together."

John's smile widens. "I know."

My throat is tight. "I save your life when I must because the idea of you dying bothers me intrinsically."

"It's all right, Sherlock," John says softly. How did he know? How did he know all this time, and I didn't?

"I don't believe in love," I say, glad to find that it's still true.

John's smile goes a little sad. "I understand that."

"But…" Curse this sodding language and all its empty spaces! There's nothing I can do but talk around the truth, getting closer and closer to it without fully touching on it. "I would die for you. I would. If I wasn't clever enough to work my way out of it."

"I prefer you alive," John says quietly, still smiling a little. He steps forward and touches my face carefully, the way one might touch a skittish animal who they suspected might bolt away at any second.

"You're maddening," I breathe, and John laughs, low and rumbly.

"You're one to talk." He leans up, slowly, carefully, giving me plenty of time to pull away. But I don't. I'm frozen in place, stock-still. His lips brush mine with infinite care; it feels like…not fire, not electricity, but something similar, something hot and wild that roils through my blood. "All right?" John asks, leaning away, his eyes worried and hopeful.

I swallow hard, my heart thrumming, and decide. "All right." And I lean back in, bringing our lips together again. After all, I'm getting much better at reciprocation.


End file.
